1. Field of the Invention
This invention relates to a U-shaped sealing material (sealing member) for reciprocating or rotational movement.
2. Description of the Related Art
As a conventional sliding (moving) sealing material (sealing member) used for oil-hydraulic or pneumatic appliances, a material (seal) as described below is known. That is to say, the sealing material is composed of a resin ring having U-shaped cross section and a concave groove, and a metal spring fit to the concave groove (refer to Japanese provisional publication No. 8-82372, and No. 2003-247646, for example) or a elastic body of rubber (refer to Japanese provisional publication of utility model No. 5-47624), and, a stage of lip is formed on a sliding face of the resin ring.
However, when the conventional sealing material is applied to medical appliances and paint appliances, liquids used in these appliances mostly tend to solidify (painting materials such as paint) or include components easily crystallize (chemicals used for hemodialysis, for example), then, sealing ability is reduced by solidified and crystallized matter sticking to near portions of the lip since only one stage of lip is formed in the conventional sealing material.
FIG. 9 shows a sealing material disclosed by the above Japanese provisional publication No. 8-82372. Bacteria may be propagated in the sealing material 31 in FIG. 9 because liquid tends to stay between a resin ring 32 and a metal spring 33 fit inside the ring and difficult to be washed off.
It is therefore an object of the present invention to provide a sealing material to seal liquids which tend to solidify and include components easily crystallize with which the sealing ability is maintained without solidified and crystallized matter sticking to near portions of the lip, the liquids do not stay in the groove of the seal main body, and cleaning is easily conducted.